mysql多表查询
@周阙1010:mysql 多表查询并排序
驷陈15993471144…… 1.查询一张表: select * from 表名; 2.查询指定字段:select 字段1,字段2,字段3….from 表名; 3.where条件查询:select 字段1,字段2,字段3 frome 表名 where 条件表达式;例:select * from t_studect where id=1; select * from t_student ...
@周阙1010:MySQL 如何多表查询 -
驷陈15993471144…… 我觉得:1. 表结构不同的话,用你的来方法比较好,速度自快. 写成这样:select count(*) from `知b` where `nid` = '123'; 直接统计出数目道了 2.表结构相同的话: 写成这样select count(*) from `a` where `nid` = '123' UNION ALL select count(*) from `b` where `nid` = '123';
@周阙1010:MYSQL多表联查 -
驷陈15993471144…… 方法一:子查询 select nam,tim from stunt where tim in (select tim from log) limit (0,5)方法一:联合查询(join) select stunt.nam,stunt,tim from stunt as s join log as l on l.tim = s.tim limit (0,5)
@周阙1010:mysql多表查询sql语句怎么写? -
驷陈15993471144…… 一使用SELECT子句进行多表查询 SELECT 字段名 FROM 表1,表2 … WHERE 表1.字段 = 表2.字段 AND 其它查询条件 SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE ...
@周阙1010:mysql 如何在多个表中查数据 -
驷陈15993471144…… select a1 ,a2 from table1 where a2='班组长' union all select a1,a2 from table2 where a2='班组长' union all select a1,a2 from table3 where a2='班组长'
@周阙1010:mysql多表查询语句 -
驷陈15993471144…… 你这两个表里没有相同的字段,那么如果两个表一起查询的时候出现的记录太多了,你也用不了.如果你想查,那么SELECT * FROM A A,B B 就行了,但我觉得这应该不是你想要的,你最好把表结构改一下,在B表里加一字段,与A表能关联起来,比如ID,SELECT * FROM A A,B B WHERE A.ID=B.ID
@周阙1010:mysql数据库,多个表的查询操作 -
驷陈15993471144…… select a.id,b.bd,c.cd from a left join b on a.bd=b.id left join c on a.cd=c.id
@周阙1010:mysql 多个表的信息怎么联合查询的 -
驷陈15993471144…… 内联接:select * from a inner join b on a.field_name=b.field_name; 左联接:select * from a left join b on a.field_name=b.field_name; 右联接:select * from a right join b on a.field_name=b.field_name; 建立外键(有2种方法0:1、建表时指定 ...
@周阙1010:MySQL 数据 库多表查询统计操作,求大神相助 -
驷陈15993471144…… 可以通过count函数来实现.sqlOne:select * from tablename1 where id>5;此语句查询出来多条记录,之后看做一个新的表.sqlTwo:select conut(*) from (select * from tablename1 where id>5) as tablename2;此语句即可查询出来统计的记录条数...
@周阙1010:mysql多表查询 -
驷陈15993471144…… select b.qq,a.pass from a inner join b on a.id=b.id where b.qq='12345' 或 select b.qq,a.pass from a,b where a.id=b.id and b.qq='12345' 以上,希望对你有所帮助!
驷陈15993471144…… 1.查询一张表: select * from 表名; 2.查询指定字段:select 字段1,字段2,字段3….from 表名; 3.where条件查询:select 字段1,字段2,字段3 frome 表名 where 条件表达式;例:select * from t_studect where id=1; select * from t_student ...
@周阙1010:MySQL 如何多表查询 -
驷陈15993471144…… 我觉得:1. 表结构不同的话,用你的来方法比较好,速度自快. 写成这样:select count(*) from `知b` where `nid` = '123'; 直接统计出数目道了 2.表结构相同的话: 写成这样select count(*) from `a` where `nid` = '123' UNION ALL select count(*) from `b` where `nid` = '123';
@周阙1010:MYSQL多表联查 -
驷陈15993471144…… 方法一:子查询 select nam,tim from stunt where tim in (select tim from log) limit (0,5)方法一:联合查询(join) select stunt.nam,stunt,tim from stunt as s join log as l on l.tim = s.tim limit (0,5)
@周阙1010:mysql多表查询sql语句怎么写? -
驷陈15993471144…… 一使用SELECT子句进行多表查询 SELECT 字段名 FROM 表1,表2 … WHERE 表1.字段 = 表2.字段 AND 其它查询条件 SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE ...
@周阙1010:mysql 如何在多个表中查数据 -
驷陈15993471144…… select a1 ,a2 from table1 where a2='班组长' union all select a1,a2 from table2 where a2='班组长' union all select a1,a2 from table3 where a2='班组长'
@周阙1010:mysql多表查询语句 -
驷陈15993471144…… 你这两个表里没有相同的字段,那么如果两个表一起查询的时候出现的记录太多了,你也用不了.如果你想查,那么SELECT * FROM A A,B B 就行了,但我觉得这应该不是你想要的,你最好把表结构改一下,在B表里加一字段,与A表能关联起来,比如ID,SELECT * FROM A A,B B WHERE A.ID=B.ID
@周阙1010:mysql数据库,多个表的查询操作 -
驷陈15993471144…… select a.id,b.bd,c.cd from a left join b on a.bd=b.id left join c on a.cd=c.id
@周阙1010:mysql 多个表的信息怎么联合查询的 -
驷陈15993471144…… 内联接:select * from a inner join b on a.field_name=b.field_name; 左联接:select * from a left join b on a.field_name=b.field_name; 右联接:select * from a right join b on a.field_name=b.field_name; 建立外键(有2种方法0:1、建表时指定 ...
@周阙1010:MySQL 数据 库多表查询统计操作,求大神相助 -
驷陈15993471144…… 可以通过count函数来实现.sqlOne:select * from tablename1 where id>5;此语句查询出来多条记录,之后看做一个新的表.sqlTwo:select conut(*) from (select * from tablename1 where id>5) as tablename2;此语句即可查询出来统计的记录条数...
@周阙1010:mysql多表查询 -
驷陈15993471144…… select b.qq,a.pass from a inner join b on a.id=b.id where b.qq='12345' 或 select b.qq,a.pass from a,b where a.id=b.id and b.qq='12345' 以上,希望对你有所帮助!